This week, we take you out in the early morning activities of the SF Bar Pilots. To start the day, we arrived at Pier 9, next door to the new Exploratorium, at 4 am at the Bar Pilots headquarters.

Who are and what are Bar Pilots you’re asking? The pilots, who are required by state law to guide ships entering or leaving the bay, have been around since the Gold Rush. What’s changed? The size of the ships (which now reach over 1,000 feet long) and the technology to accomplish the job.

The Bar Pilots are on call 24 hours a day, 365 days a year, to safely deliver cargo and passengers, boarding each ship via a rope ladder. Once on the bridge of the ship, the Bar Pilot takes control of the navigation and directs the ship into the Bay. In terms of piloting, San Francisco Bay is considered one of the most complex harbors in the United States.

For five hours one typical morning, we documented these brave men and women keep the SF Bay's commercial vessels safe.

Enjoy the photo essay.